Expression levels of LOXL2 are highly correlated with the severity of pulmonary fibrosis, and LOXL2 expression is significantly increased in serum, lung homogenate, and lung tissue of bleomycin-induced pulmonary fibrosis mice, critical for the transformation of fibroblasts into myofibroblasts via the TGF-β/Smad pathway. This evidence concerns the gene TGFB1 and pulmonary fibrosis.